To break or fail to keep a promise; to go back on one's word.
From dis- (negation) + promise (from Old French promesse, ultimately from Latin promittere). The prefix reverses the commitment into a betrayal.
Shakespeare's contemporaries used this word to describe oath-breaking, especially in contexts of betrayal—it carries more weight than our modern 'break a promise' because it treats promise-breaking as its own distinct action.
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